Symptom: a Jetta city pioneer mileage: 1500km. When the shift lever is set to "R", the lever locks the electromagnet "click and click".
    Troubleshooting: the shift lever to the "R" file, lock the electromagnet "click, click" ring, hand touch the wheel has a sense of vibration, try to push the shift lever to other gear, no exception. As shown in Fig. 1, the shift lever lock solenoid is located at the lower part of the shift lever and is controlled by an automatic transmission control unit (transmission ECU), which functions to release the lock when the ignition switch is depressed and the brake pedal is depressed , The shift lever can be pushed to other gears; otherwise, the solenoid is in the locked state, to prevent the shift lever slide to other gears. It can be seen, locking the electromagnet "click, click" ring with the transmission ECU.
    Connect the Volkswagen special fault reader V.A.G1551, enter 1 (select the quick data transmission function) -02 (automatic transmission address code), press "Q" key to confirm, the result shows "electronic control unit no answer". The electronic control unit can not be accessed, should first check whether the normal power supply. See Figure 2, the electronic control unit a total of 68 feet, the 1 foot ground, 45 feet then 30, 23 feet then 15, 60 feet by 14 fuse 15 power. After checking the above-mentioned power supply are normal, suspected electronic control unit damage, replace the electronic control unit, the shift lever to the "R" file, shift lever lock electromagnet no longer "click, click" ring, with VA G1551 check can also be accessed, troubleshooting.
    Automatic transmission control unit controls all electrical and hydraulic functions of the transmission, controlled by fuzzy logic, can meet the requirements of different drivers driving, can identify uphill, with trailers, wind and downhill and other driving resistance. In the emergency state, if the control unit is faulty, the 1st gear hydraulic, the third gear and the "R" reverse are still valid. These gears can be shifted in the slide valve by operating the shift lever. In the shift lever position "D" , The hydraulic pressure to start by 3 files. According to the repair experience, if the electronic control unit damage or remove the electronic control unit, the transmission to start the emergency state, the general driver and passengers will not have a clear feeling, so the user is "R" file abnormal sound failure, To the service station repair.